Precast News From China
The performance evaluation indicators of concrete are key parameters for measuring the quality of concrete, which directly affect the reliability and service life of concrete structures, mainly including the workability, strength, durability, and economy of concrete, as shown in Table 1.
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As practitioners in the concrete industry, we have gone through a difficult time together in the past two years.
The sluggish real estate market, insufficient project funding, worsening market competition, and meager or even loss making corporate profits undoubtedly put pressure on many mixing plant owners and management, and even begin to doubt whether this industry is still worth sticking to.
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Climate conditions (such as freeze-thaw cycles) may cause freeze-thaw damage, which needs to be prevented by optimizing mix proportions (such as adjusting aggregate gradation) or adding antifreeze agents.
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When pouring concrete, the skilled workers followed the specifications for operation, and the vibration was done very solidly, and the surface was also applied very neatly.
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According to the report of the World Business Council for Sustainable Development (WBCSD), the world’s annual concrete production exceeds 25 billion tons, with a huge demand.
Fine aggregates can reduce cement content by 10% to 15% through gradation optimization, while ensuring the dimensional stability of concrete.
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Thank you very much for using our company’s commercial concrete for your project.
Our company attaches great importance to your project, strictly organizing production in accordance with relevant regulations and requirements, from the design and control of raw materials entering the factory, mix proportions, to the control of concrete leaving the factory.
However, concrete is often affected by various factors during delivery and use.
If effective measures are not taken during construction and maintenance, it may cause quality problems.
Therefore, our company proposes the following suggestions for concrete construction:.
Tang Kaijing and others studied basalt mechanism sand, river sand, and quartz mechanism sand, and found that different rock types of mechanism sand have a significant impact on the workability of C50 concrete.
Differences in morphology and gradation are the reasons for the decrease in workability.
Donza et al.
conducted a comparative study on the workability of limestone, granite, dolomite mechanism sand, and natural sand concrete, and found that the chemical mineral composition, rock type, bulk density, and internal structure of the mechanism sand parent rock are the main factors affecting the performance of mechanism sand.
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The climate characteristics of autumn show significant changes in temperature, humidity, and wind speed (daily average temperature of 5-20 ℃, temperature difference between day and night of 8-15 ℃, relative humidity of 40% -80%), which directly affects the concrete from mixing, pouring, curing to hardening and forming.
According to the “Winter Construction Regulations for Building Engineering” (JGJ/T104-2011), concrete quality problems caused by climate factors in autumn account for more than 35% of the total annual amount, with particularly prominent issues such as cracks, insufficient strength, and surface defects.
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Phenomenon: Cracks that settle due to bleeding or shrinkage of concrete within 1-3 hours after pouring.
The settlement crack cracks along the direction of the main reinforcement on the surface of the beam and slab, and the crack extends as deep as the surface of the reinforcement.
Plastic shrinkage cracks produce irregular diagonal cracks above the steel bars.
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In the field of engineering construction, concrete is the main load-bearing material, and its strength grade is directly related to structural safety and service life.
According to the “Code for Design of Concrete Structures” (GB/T50010-2010), different engineering parts have strict requirements for concrete strength.
For ordinary homebuyers, when they discover quality problems such as cracks and component deformation in their houses, they can learn about the strength of the concrete through the following methods.
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